Corundum(alpha)

Formula : Al2O3

Space group: 
Trigonal - Hexagonal Scalenohedral H-M Symbol (3 2/m) Space Group: R 3c
Dana class: 
4.3.1.1 (4) Simple Oxides (4.3) with a cation charge of 3+ (A+++2 O3)(4.3.1) Corundum-Hematite group (Rhombohedral: R3_c)
High temperature: 
High temperature mineral, related to metamorphisme and udersaturated magmas.
Geological context: 
Contact and regionally metamorphosed rocks but also in magma with low silica content (alkaline context)

Dernière mise à jour le 11.06.2018

THERMODYNAMICS

Individual properties (298.15 K)
M
g·mol-1
cm3·mol-1
ΔGºf
J·mol-1
ΔHºf
J·mol-1
J·mol-1·k-1
CP
J·mol-1·K-1
101.961 25.580 -1582257 -1675700 50.920 79.03
Reaction properties

Corundum(alpha) + 6H+ ⇌ 2Al+3 + 3H2O

298.15 K, 1 bar log10K: 18.30 ΔH°r: -258590 J·mol-1
T(°C) 0 25 60 100 150 200 250 300
log10K 22.42 18.30 13.51 9.08 4.60 0.87 -2.39 -5.41